I have not worked with the 202 and QOS but maybe I can help. First, is your wireless traffic heavy? It seems that the router is built to either do better QoS for wireless or wired by a number of tricks such as giving priority to an ethernet port. If you assigned the port that the Obi is plugged into then you should get better QoS for wired.
That is shown here:
http://setuprouter.com/router/linksys/wrtu54g-tm/qos-7253-large.htmYou can't really (effectively) throttle inbound traffic and it sounds like your bottleneck is up which is often more limited than down.
In addition to what more real world you get from others, I'd test by turning EVERYTHING off that is wireless and see if there is a difference.
And it looks like the "TM" isn't evil but who knows.
For my deployment I am going to use Tomato on a router that is compatible with yours. This can get very granular and if you have to use a cable modem as the final jump to the outside, you should see better results on both wired and wireless. I already have the router locked and loaded I just need to introduce a new subnet.
Tomato is pretty technical but if you are operating with an Obi you should be ready for it. Backup the config in the Linksys if you can or find a way to flash it back if something goes wrong. You can always pick up something compatible if something goes wrong. I'm using a couple of Asus routers though I don't know where the second one is.
I'll try to get this done over the weekend so I can share real world advise. I have 750gb of data that I'm uploading to Onedrive and everything pukes on that including Netflix which is mostly down.
If you're not familiar with Tomato here are notes for your specific router:
https://en.wikibooks.org/wiki/Tomato_Firmware/Supported_Devices#Linksys_WRT54G-TMNote that the next models are Asus which you can pick up from Amazon. The WRT54G is stuff of legends. You have a (pink) version (so to speak) but at least you have the "WRT54G".